They Hoped a DNA Test Would Clear Him. It Did the Opposite.

A recent DNA test showed that a man who was found not guilty in the murder of a horse groomer at a Florida racetrack more than 30 years ago was, in fact, the killer, the authorities said on Wednesday.

Lawyers for the man, Robert Earl Hayes, had asked investigators in 2020 to retest the strands of hair found in the hand of the horse groomer, Pamela Albertson, after she was raped and killed in February 1990 at the Pompano Beach racetrack in South Florida, where they both worked. The lawyers believed that the findings would help exonerate their client in the 1987 killing of another racetrack worker in Oneida County, N.Y., for which Mr. Hayes is currently in prison.

In the New York case, Mr. Hayes pleaded guilty to manslaughter, arson and burglary in 2004. He was sentenced to 15 to 45 years in prison and is eligible for parole in 2025.

But investigators also retested vaginal DNA collected from Ms. Albertson, and found that it was a match with Mr. Hayes, effectively proving that he was guilty all along, said Harold F. Pryor, the Broward County state attorney in Florida.

Mr. Pryor cannot retry Mr. Hayes, now 58, in the Florida case because the Constitution prohibits people from being retried for substantially the same crime if they were already acquitted. But Mr. Pryor is asking the parole board in New York to keep Mr. Hayes in custody.

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Mr. Hayes was initially convicted of raping and murdering Ms. Albertson in 1991 and sentenced to death, Mr. Pryor said in a statement. But the conviction was overturned by the Florida Supreme Court in 1995 after it questioned the reliability of the original DNA test, which was one of the first of its kind in the state, he said.

The court’s ruling had stemmed from a technique of DNA testing called “band-shifting” that it deemed unreliable. It involved slightly tweaking the bands on a DNA test, which would have been on X-ray film in the 1990s, said Dan Krane, a professor of biology at Wright State University who has researched tools to evaluate DNA evidence for criminal investigations.

“The court was saying, if the band-shifting didn’t occur, this wouldn’t be a good match,” Professor Krane said.

That evidence was not allowed during the second trial. A Florida jury found Mr. Hayes not guilty at a retrial in 1997.

In the 1990s, DNA tests required a much larger sample size to be effective, like a blood stain the size of a quarter, Professor Krane said.

Now, the quantity needed for an accurate DNA test is too small for the naked eye to see. {snip}

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Mr. Hayes’s association with the Florida case led the authorities in New York to charge him with manslaughter in the 1987 killing of Leslie Dickenson, a horse groomer at the Vernon Downs racetrack, 40 miles east of Syracuse.

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